WEB-1683: Selection Extension Fixes

[AlexandruPopovici]

Description & motivation

SelectionExtension now clears it's selected objects state when clearing the selection. It also does not allow for duplicate selected nodes anymore

Changes:

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References

[linear]

WEB-1683 SelectionExtension does not reset selected objects state when deselecting

[github-actions]

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